L-Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system, which activates several subtypes of ionotropic and metabotropic receptors. The ionotropic receptors can be divided into three subtypes, which are defined by the depolarizing actions of the selective agonists N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), and kainic acid (KA).
AMPA receptors are assembled from four protein sub-units known as GluR1 to GluR4, while kainic acid receptors are assembled from the sub-units GluR5 to GluR7, and KA-1 and KA-2.
AMPA receptors have been associated with diseases and conditions as diverse as memory and learning disorders, a psychotic disorder, sexual dysfunction, an intellectual impairment disorder, schizophrenia, depression, autism, Alzheimer's disease, learning deficit, attention deficit, memory loss, and senile dementia, or from a disorder or disease resulting from trauma, from stroke, from epilepsy, from Alzheimer's disease, from a neurotoxic agent, from aging, from a neurodegenerative disorder, from alcohol intoxication, from substance abuse, from cardiac bypass surgery or from cerebral ischemia.